Assessment of DNA interstrand crosslinks in NIH/3T3 cells induced by Chloroethylnitrosoureas

Aim: To investigated the mechanism of Chloroethylnitrosoureas (CENUs) leading to secondary tumors after therapy, three kinds of CENUs, namely, Nimustine (ACNU), Carmustine (BCNU) and Semustine (MeCCNU) were used to investigated drug-induced DNA interstrand crosslinks(ICLs). Method: The alkaline comet assay was adopted to compare DNA damages induced by CENUs under different concentrations. Results: With the increase of drug’s concentration, DNA migration exhibited a positive concentration-dependent relationship in all three drugs. ACNU was shown to cause significant crosslinking. The other two drugs also induced crosslinking, but this could not be analyzed at high concentrations due to the high cytotoxicity of the drugs which caused cells death.